Risk factors of visceral leishmaniasis: a case control study in north-western Ethiopia

Background Visceral leishmaniasis (VL, also called “kala-azar”), is a life threatening neglected tropical infectious disease which mainly affects the poorest of the poor. VL is prevalent in Ethiopia particularly in the northwest of the country. Understanding the risk factors of VL infection helps in its prevention and control. The aim of the present study was to identify the factors associated with VL. Methods A case–control study was carried out during the period of January-July 2013 in northwest Ethiopia. Cases and controls were diagnosed using clinical presentation, the rk39 rapid diagnostic test and Direct Agglutination Test (DAT). A total of 283 (84.8% males versus 15.2% females) participants were interviewed. 90 cases and 193 controls were involved, matched by age, sex and geographical location with a ratio of 1:2 (case: controls). Univariate and backward multivariate conditional logistic regression were used to identify risk factors of VL. Results Elevated odds of VL was associated with goat ownership (OR = 6.4; 95%: confidence interval [Cl]: 1.5-28.4), living in houses with cracked wall (OR = 6.4; 95% Cl: 1.6-25.6), increased family size (OR = 1.3; 95% Cl: 1.0-1.8) and the number of days spent in the farm field (OR = 1.1; 95% Cl: 1.0-1.2). However, daily individual activities around the home and farm fields, mainly sleeping on a bed (OR = 0.2; 95%: Cl 0.03-0.9), sleeping outside the house under a bed net (OR = 0.1; 95% Cl: 0.02-0.36)] and smoking plant parts in the house during the night time (OR = 0.1; 95% Cl: 0.01-0.6) were associated with decreased odds of being VL case. Conclusion Our findings showed that use of bed net and smoke could be helpful for the prevention of VL in the area particularly among individuals who spend most of their time in the farm. VL control effort could be focused on improving housing conditions, such as sealing cracks and crevices inside and outside houses. Further research is warranted to elucidate the role of goats in the transmission of L. donovani, assess the impact of bed nets and the role of the traditional practice of smoking plants

Nanorings and rods interconnected by self-assembly mimicking an artificial network of neurons

[EN] Molecular electronics based on structures ordered as neural networks emerges as the next evolutionary milestone in the construction of nanodevices with unprecedented applications. However, the straightforward formation of geometrically defined and interconnected nanostructures is crucial for the production of electronic circuitry nanoequivalents. Here we report on the molecularly fine-tuned self-assembly of tetrakis-Schiff base compounds into nanosized rings interconnected by unusually large nanorods providing a set of connections that mimic a biological network of neurons. The networks are produced through self-assembly resulting from the molecular conformation and noncovalent intermolecular interactions. These features can be easily generated on flat surfaces and in a polymeric matrix by casting from solution under ambient conditions. The structures can be used to guide the position of electron-transporting agents such as carbon nanotubes on a surface or in a polymer matrix to create electrically conducting networks that can find direct use in constructing nanoelectronic circuits.The research leading to these results has received funding from ICIQ, ICREA, the Spanish Ministerio de Economia y Competitividad (MINECO) through project CTQ2011-27385 and the European Community Seventh Framework Program (FP7-PEOPLE-ITN-2008, CONTACT consortium) under grant agreement number 238363. We acknowledge E. C. Escudero-Adan, M. Martinez-Belmonte and E. Martin from the X-ray department of ICIQ for crystallographic analysis, and M. Moncusi, N. Argany, R. Marimon, M. Stefanova and L. Vojkuvka from the Servei de Recursos Cientifics i Tecnics from Universitat Rovira i Virgili (Tarragona, Spain).Escarcega-Bobadilla, MV.; Zelada-Guillen, GA.; Pyrlin, SV.; Wegrzyn, M.; Ramos, MMD.; Giménez Torres, E.; Stewart, A.... (2013). 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Anisotropic nanomaterials: structure, growth, assembly, and functions

Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications

Deagrarianisation and forest revegetation in a biodiversity hotspot on the Wild Coast, South Africa

Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa’s Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape

Comparative evaluation of methods for the detection of biofilm formation in coagulase-negative staphylococci and correlation with antibiogram

Lok Bahadur Shrestha, Narayan Raj Bhattarai, Basudha Khanal Department of Microbiology and Infectious Diseases, B. P. Koirala Institute of Health Sciences, Dharan, Nepal Introduction: Coagulase-negative staphylococci (CNS) are normal commensals of human skin and mucous membranes. The objective of the study was to determine the prevalence of CNS among clinical isolates, characterize them up to species level, compare the three conventional methods for detection of biofilm formation, and study their antimicrobial susceptibility pattern.Materials and methods: CNS were obtained from various clinical samples including blood, urine, central venous catheter tips, endotracheal tube aspirate, and pus during a 1-year period (July 1, 2014, to June 30, 2015). Characterization up to species level was done using biochemical tests, and biofilm formation was detected by tube adherence, Congo red agar, and tissue culture plate method. Antimicrobial susceptibility testing was performed following Clinical and Laboratory Standards Institute guidelines.Results: A total of 71 CNS isolates, comprising of seven species were obtained. Staphylococcus epidermidis was the most common species followed by S. saprophyticus and S. haemolyticus. We detected biofilm formation in 71.8% of isolates. Considering the fact that tissue culture plate method is the gold standard, sensitivity of tube adherence method and Congo red agar method was found as 82% and 78%, respectively. The isolates exhibited high resistance toward penicillin (90%), azithromycin (60%), co-trimoxazole (60%), and ceftriaxone (40%), while all were susceptible to vancomycin and linezolid. Biofilm former isolates showed higher resistance than the non-formers.Conclusion: Among 71 CNS isolated, S. epidermidis was the most common isolate followed by S. saprophyticus and S. haemolyticus. Biofilm formation was detected in 71.8% of the isolates. All of the methods were effective in detecting biofilm-producing CNS strains. The antimicrobial resistance was significantly higher in biofilm formers than non-formers. Keywords: CNS, Congo red agar, bloodstream infections, foreign body-related infections, tissue culture plat

Antibiotic resistance and biofilm formation among coagulase-negative staphylococci isolated from clinical samples at a tertiary care hospital of eastern Nepal

Background Coagulase negative staphylococci were long regarded non-pathogenic as they are the commensals of human skin and mucosa but the recent changes in the medical practice and changes in underlying host populations, they are being considered significant pathogens associated with number of nosocomial infections. The objective of the study was to determine the species, antimicrobial susceptibility pattern, biofilm forming ability of the clinically significant CoNS isolates and to compare the different methods for the detection of biofilm formation. Methods A total of 52 clinically significant CoNS isolates obtained from different units during a year period were studied. Characterization was done using standard microbiological guidelines and antimicrobial susceptibility was done following CLSI guidelines. Biofilm formation was detected by using three methods i.e. tissue culture plate method, congo red agar method and tube adherence method. Results Among 52 isolates, S. epidermidis (52%) was the most common species which was followed by S. saprophyticus (18%) and S. haemolyticus (14%). Antimicrobial susceptibility pattern of CoNS documented resistance of 80% to ampicillin. Resistance to cefoxitin and ceftriaxone was observed in 58% of the isolates. Biofilm formation was observed in 65.38% of the isolates. The accuracy of Congo red agar and tube adherence method for the detection of biofilm formation was 82% and 76% respectively. Conclusion CoNS isolates obtained from clinical samples should be processed routinely and antimicrobial susceptibility testing should be performed. Multidrug-resistant CoNS are prevalent. All the three methods i.e. tissue culture plate, Congo red agar and tube adherence method can be used in detecting biofilm formation

Comparative evaluation of methods for the detection of biofilm formation in coagulase-negative staphylococci and correlation with antibiogram

Lok Bahadur Shrestha, Narayan Raj Bhattarai, Basudha Khanal Department of Microbiology and Infectious Diseases, B. P. Koirala Institute of Health Sciences, Dharan, Nepal Introduction: Coagulase-negative staphylococci (CNS) are normal commensals of human skin and mucous membranes. The objective of the study was to determine the prevalence of CNS among clinical isolates, characterize them up to species level, compare the three conventional methods for detection of biofilm formation, and study their antimicrobial susceptibility pattern.Materials and methods: CNS were obtained from various clinical samples including blood, urine, central venous catheter tips, endotracheal tube aspirate, and pus during a 1-year period (July 1, 2014, to June 30, 2015). Characterization up to species level was done using biochemical tests, and biofilm formation was detected by tube adherence, Congo red agar, and tissue culture plate method. Antimicrobial susceptibility testing was performed following Clinical and Laboratory Standards Institute guidelines.Results: A total of 71 CNS isolates, comprising of seven species were obtained. Staphylococcus epidermidis was the most common species followed by S. saprophyticus and S. haemolyticus. We detected biofilm formation in 71.8% of isolates. Considering the fact that tissue culture plate method is the gold standard, sensitivity of tube adherence method and Congo red agar method was found as 82% and 78%, respectively. The isolates exhibited high resistance toward penicillin (90%), azithromycin (60%), co-trimoxazole (60%), and ceftriaxone (40%), while all were susceptible to vancomycin and linezolid. Biofilm former isolates showed higher resistance than the non-formers.Conclusion: Among 71 CNS isolated, S. epidermidis was the most common isolate followed by S. saprophyticus and S. haemolyticus. Biofilm formation was detected in 71.8% of the isolates. All of the methods were effective in detecting biofilm-producing CNS strains. The antimicrobial resistance was significantly higher in biofilm formers than non-formers. Keywords: CNS, Congo red agar, bloodstream infections, foreign body-related infections, tissue culture plat

Incidence of symptomatic and asymptomatic Leishmania donovani infections in high-endemic foci in India and Nepal: a prospective study.

Incidence of Leishmania donovani infection and Visceral Leishmaniasis (VL) was assessed in a prospective study in Indian and Nepalese high-endemic villages. DAT-seroconversion was used as marker of incident infection in 3 yearly surveys. The study population was followed up to month 30 to identify incident clinical cases. In a cohort of 9034 DAT-negative individuals with neither active signs nor history of VL at baseline, 42 VL cases and 375 asymptomatic seroconversions were recorded in the first year, giving an infection:disease ratio of 8.9 to 1. In the 18 months' follow-up, 7 extra cases of VL were observed in the seroconverters group (N=375), against 14 VL cases among the individuals who had not seroconverted in the first year (N=8570) (RR=11.5(4.5<RR<28.3)). Incident asymptomatic L. donovani infection in VL high-endemic foci in India and Nepal is nine times more frequent than incident VL disease. About 1 in 50 of these new but latent infections led to VL within the next 18 months